{#- -*- coding: utf-8 -*- #}
{#- vim: ft=jinja #}

{#- Get the `tplroot` from `tpldir` #}
{%- set tplroot = tpldir.split("/")[0] %}

{%- macro mapstack(
      files,
      defaults=None,
      log_prefix="libmapstack: "
    ) %}
{#-
    Load YAML files in the order of `files` and merge successively the
    values with `defaults` if the file exists.

    Parameters:
      - `files`: list of files to load

      - `defaults`: default values to start the merging, they are
        considered built-ins

      - `log_prefix`: prefix used in the log outputs, by default it is
        `libmapstack: `

    Each YAML file must conform to the following layout:
      - a mandatory `values` key to store the configuration values

      - two optional keys to configure the use of `salt.slsutil.merge`

        - an optional `strategy` key to configure the merging strategy,
          for example `strategy: 'recurse'`, the default is `smart`

        - an optional `merge_lists` key to configure if lists should be
          merged or overridden for the `recurse` and `overwrite`
          strategies, for example `merge_lists: 'true'`
#}
{%-   set stack = defaults | default({"values": {} }, boolean=True) %}

{%-   do salt["log.debug"](
        log_prefix
        ~ "built-in configuration:\n"
        ~ {"values": defaults | traverse("values")}
        | yaml(False)
      ) %}

{%-   for yaml_filename in files %}
{%-     do salt["log.debug"](
          log_prefix
          ~ "load configuration values from "
          ~ yaml_filename
        ) %}

{%-     load_yaml as yaml_values %}
{%-       include yaml_filename ignore missing %}
{%-     endload %}

{%-     do salt["log.debug"](
          log_prefix
          ~ "loaded configuration values from "
          ~ yaml_filename
          ~ ":\n"
          ~ yaml_values
          | yaml(False)
        ) %}

{%-     if yaml_values %}
{#-       Per YAML file `salt["slsutil.merge"]` options or use defaults #}
{%-       set _strategy = yaml_values
            | traverse(
              "strategy",
              defaults
              | traverse(
                "strategy",
                "smart"
              )
            ) %}
{%-       set _merge_lists = yaml_values
            | traverse(
              "merge_lists",
              defaults
              | traverse(
                "merge_lists",
                False
              )
            )
            | to_bool %}

{#-       Update only the `values`, the `salt["slsutil.merge"]` options are never updated #}
{%-       do stack.update(
            {
              "values": salt["slsutil.merge"](
                stack["values"],
                yaml_values
                | traverse("values", {}),
                strategy=_strategy,
                merge_lists=_merge_lists,
              )
            }
          ) %}
{%-       do salt["log.debug"](
            log_prefix
            ~ "merged configuration values from "
            ~ yaml_filename
            ~ ", merge: strategy='"
            ~ _strategy
            ~ "', merge_lists='"
            ~ _merge_lists
            ~ "':\n"
            ~ {"values": stack["values"]}
            | yaml(False)
          ) %}
{%-     endif %}

{%-   endfor %}

{%-   do salt["log.debug"](
        log_prefix
        ~ "final configuration values:\n"
        ~ {"values": stack["values"]}
        | yaml(False)
      ) %}

{#- Output stack as YAML, caller should use with something like #}
{#- `{%- set config = flexible_config(prefix="foo") | load_yaml %}` #}
{{ stack | yaml }}

{%- endmacro %}